Anyone attended patient’s funeral before? Any advice would be grateful

Long story short I had a lovely patient and he passed away. I received funeral information from his wife and would like to attend. However I’m a dumb and inexperienced young person who has never attended a funeral in my life. The only thing I know is that I need to wear formal black clothes. How does the funerals go, generally? I’m quite timid and don’t have great social skills. Do I have to talk to people? I assume it will be like a church service so can I just attend, sit at the back and leave once everything’s finished? And it’s not weird for a nurse to attend a patient’s funeral, right? Or is it uncommon and weird? It would be great if anyone can teach me some codes and etiquettes. I don’t have anyone to ask about these things. Thank you!